1. Field of the Invention
The present invention relates to lens driving devices, and more particularly, to a miniature magnetic-levitated lens driving device wherein an optical lens module is magnetically suspended in a casing by a magnetic-levitated module and powered by an electromagnetic field.
2. Description of the Prior Art
Referring to FIG. 1, there is shown an exploded perspective view of a conventional focusing lens. As shown in the drawing, a mechanical-transmission focusing mechanism 9 for use with the conventional focusing lens comprises a high-cost high-precision driving component 91 (such as a stepping motor, ultrasonic motor, or piezoelectric actuator), a carrier 93 provided with a lens module 92 and driven by the driving component 91, and lots of transmission components. Hence, the conventional focusing lens is complicated in terms of its mechanical framework, difficult and intricate to assemble, bulky, expensive, power-consuming, and thus price-uncompetitive.
Primitive photography was complicated, as it required taking laborious steps, such as manual light metering, manual focusing, and automatic winding, and the laborious steps predisposed users to mistakes. Primitive photography was especially demanding when performed at important scenes which offer a once-in-a-lifetime opportunity of taking important pictures. Hence, photographers played a crucial role in successful application of primitive photography. The 1950s and 1960s saw remarkable advancement of mechanical automation, and thus human beings are increasingly assured that automation is going to be the yardstick of a promising world. Automatic light metering techniques and electric winders developed earlier are sufficient proofs that photography is likely to undergo automation. The most important factor in automation of primitive photography is the photographic speed-determining step essential to an automatic focusing system, which was therefore regarded as a hot R&D topic by camera manufacturers at that time.
With ever-improving photographic technology, approaches to improving display quality and implement miniaturization of photographic devices are often proposed in hopes of meeting the demand for diversified products in the information era. However, a zooming lens mechanically driven by a stepping motor has a drawback, that is, no chance of further miniaturizing the zooming lens, which is a factor in failure to miniaturize products.
Manufacturers apply electromagnetic technology and use a VCM (Voice. Coil Motor) electronic feedback system to monitor a coil offset so as to dispense with conventional stepping motors, thereby further downsizing a driving structure. Also, manufacturers implement integration of products of different functions by, for example, integrating a photographic function into a cell phone configured for mobile communication, integrating a photographic function into a personal digital assistant (PDA), or integrating a photographic function into a notebook computer, so as to enhance video-related functions of cell phones, PDAs, or notebook computers.
Accordingly, related R&D carried out by manufacturers involves reducing the size, cutting the costs, and reducing power consumption of products that share a power supply device, so as to efficiently increase standby duration and usage duration of the products that share the power supply device while the capacity of the power supply device remains unchanged.